Ablation device

ABSTRACT

A method and system for achieving hemostasis (the stoppage of bleeding) is described. RF (radio frequency) energy is used to ablate the surface of tissue to stop bleeding. The depth of destruction of the tissue can be controlled so as to desiccate and coagulate the tissue. In one implementation, an electrode carrier including bipolar electrodes is applied to the tissue, and RF energy transmitted through the bipolar electrodes to ablate the tissue. A layer of desiccated tissue can be created as well as coagulation of the tissue to achieve hemostasis.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.11/118,653, filed Apr. 28, 2005, now U.S. Pat. No. 7,674,260, thecontents of which are hereby incorporated by reference in their entiretyas part of the present disclosure.

TECHNICAL FIELD

This invention relates to a medical device and procedure.

BACKGROUND

A trauma victim with a wound to certain organs in the body can be atsignificant risk of bleeding to death if the bleeding cannot be quicklycontrolled. For example, the liver is formed from a parenchymatous(porous) tissue that can bleed profusely when injured. A conventionaltechnique for controlling the bleeding is to apply immediate pressure tothe tissue, however, as soon as the pressure is removed, the bleedingcan resume. Gauze type products, such as QuikClot® are available, thatinclude a hemostatic agent to promote blood clotting. However, whenapplied to an organ like the liver, removing the gauze can reopen thewound, leading to additional bleeding. To prevent a trauma victim frombleeding to death, bleeding must be stopped immediately and often cannotwait until a victim is transferred to a medical facility.

SUMMARY

This invention relates to a medical device and procedure. In general, inone aspect, the invention features an apparatus for substantiallyachieving hemostasis by tissue ablation. The apparatus includes a basemember, an electrode carrier, a vacuum line and a controller. Theelectrode carrier is attached to a surface of the base member andincludes one or more bipolar electrodes that are configured to connectto a source of radio frequency energy. The vacuum line is configured toconnect to a vacuum source and to draw moisture away from the one ormore bipolar electrodes during tissue ablation. The controller iselectrically coupled to the electrode carrier and configured to controlthe delivery of radio frequency energy to the one or more bipolarelectrodes, such that tissue in contact with the electrode carrier canbe ablated to a desired depth of destruction to achieve substantialhemostasis.

In general, in another aspect, the invention features a system forsubstantially achieving hemostasis by tissue ablation. The systemincludes a hemostasis device, a source of radio frequency, a controllerand a vacuum source. The hemostasis device includes a base member, anelectrode carrier and a vacuum line. The electrode carrier is attachedto a surface of the base member and includes one or more bipolarelectrodes. The one or more bipolar electrodes are configured to connectto the source of radio frequency energy. The vacuum line is configuredto connect to the vacuum source. The source of radio frequency energy iselectrically coupled to the one or more bipolar electrodes. Thecontroller is configured to control the delivery of radio frequencyenergy from the source of radio frequency energy to the one or morebipolar electrodes, such that tissue can be ablated to a desired depthof destruction to achieve substantial hemostasis. The vacuum source iscoupled to the vacuum line and operable to draw bleeding tissue intocontact with the electrode carrier and to draw moisture generated duringdelivery of radio frequency energy to the one or more bipolar electrodesand ablation of the tissue away from the one or more bipolar electrodes,and to substantially eliminate liquid surrounding the one or morebipolar electrodes.

Implementations of the system or apparatus can include one or more ofthe following features. The apparatus can further include a porous layerpositioned between the base member and the electrode carrier, the porouslayer coupled to the vacuum line. The base member and the electrodecarrier attached thereto can be substantially flexible, alternatively,the base member can be substantially rigid. In one embodiment, the basemember is a glove including a palm region and finger regions and theelectrode carrier is attached to the palm region of the base member. Theglove can include one or more additional electrode carriers attached tothe finger regions.

The electrode carrier can include woven strips of a non-conductivematerial, where the one or more bipolar electrodes include electrodewires woven in a first direction between the strips of non-conductivematerial. In one embodiment, sets of two or more electrode wires arewoven in a first direction between each strip of non-conductive materialorientated in the first direction, where each set of electrode wiresalternates polarity, and a pair of sets of electrode wires comprises abipolar electrode. The base member can be substantially cylindricallyshaped, and the electrode carrier attached to an exterior surface of thecylindrically shaped base member. A second electrode carrier can beattached to an interior surface of the cylindrically shaped base member.

In general, in another aspect, the invention features a method for bloodcoagulation. An electrode carrier of a hemostasis device is positionedin contact with bleeding tissue. The hemostasis device includes a basemember, the electrode carrier attached to a surface of the base member,the electrode carrier including one or more bipolar electrodes connectedto a source of radio frequency energy, and a vacuum line connected to avacuum source. A vacuum source is activated to draw the bleeding tissueinto closer contact with the electrode carrier and to draw moisturereleased from the tissue during ablation away from the one or morebipolar electrodes. The source of radio frequency energy is activatedand radio frequency energy is delivered to the one or more bipolarelectrodes and ablates the tissue in contact with the one or morebipolar electrodes. The delivery of the radio frequency energy is ceasedupon reaching a desired depth of destruction of the tissue. Hemostasisis substantially achieved in a region of the ablation.

In general, in another aspect, the invention features an apparatus forachieving hemostasis by tissue ablation including a base member shapedas a glove configured to be worn by a user. The apparatus furtherincludes an electrode carrier attached to a surface of the base memberand a controller. The electrode carrier includes one or more bipolarelectrodes that are configured to connect to a source of radio frequencyenergy. The controller is electrically coupled to the electrode carrierand configured to control the delivery of radio frequency energy to theone or more bipolar electrodes, such that tissue in contact with theelectrode carrier can be ablated to a desired depth of destruction toachieve substantial hemostasis.

Implementations of the apparatus can include one or more of thefollowing. A porous layer can be positioned between the base member andthe electrode carrier, the porous layer including a vacuum lineconfigured to connect to a vacuum source and to draw moisture away fromthe one or more bipolar electrodes during tissue ablation. The basemember can include a palm region and finger regions and the electrodecarrier can be attached to the palm region of the base member. Theapparatus can include one or more additional electrode carriers attachedto undersides of the finger regions of the base member. The base membercan include a main region corresponding to the hand of a glove andfinger regions corresponding to fingers of a glove where the electrodecarrier is attached to a top side of the main region opposite to a palmside of the main region. One or more additional electrode carriers canbe attached to top sides of the finger regions of the base member.

The electrode carrier or carriers can include woven strips of anon-conductive material, where the one or more bipolar electrodesinclude electrode wires woven in a first direction between the strips ofnon-conductive material. In another embodiment, sets of two or moreelectrode wires are woven in a first direction between each strip ofnon-conductive material orientated in the first direction, where eachset of electrode wires alternates polarity, and a pair of sets ofelectrode wires is a bipolar electrode.

Implementations of the invention can realize one or more of thefollowing advantages. Hemostasis, the stoppage of bleeding, can beachieved quickly and in difficult to access locations in a patient'sbody. The hemostasis device can be used in trauma situations, such asthe battleground, accident scenes or an emergency room, to quicklycontrol bleeding and prevent the patient from bleeding to death. Tissuetypes that can bleed profusely and are difficult treat can be treatedusing the hemostasis device. The liver is a good example, as bleedingfrom the liver can be difficult to control, even under operating roomconditions. The hemostasis device can have different configurations thatare suited to different applications, for example, the device can beflexible, rigid, shaped as a glove, shaped cylindrically, etc. The depthof destruction of the tissue can be controlled so as to desiccate andcoagulate the superficial tissue, without causing additional orunnecessary injury. The electrode carrier on the hemostasis device canbe removed without restarting the bleeding, nor does pressure need to beapplied after desiccation is complete.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1A is a schematic representation of a hemostasis device.

FIG. 1B is a schematic representation of an alternative embodiment ofthe hemostasis device of FIG. 1A.

FIG. 2 is an enlarged view of a portion of an electrode carrier.

FIG. 3 is an enlarged cross-sectional view of a portion of an electrodecarrier.

FIG. 4 is a schematic representation of a system including a hemostasisdevice.

FIG. 5 is a side view of a portion of a hemostasis device in contactwith tissue.

FIG. 6 is a flowchart showing a process for coagulating blood using ahemostasis device.

FIGS. 7A-D are schematic representations of cross-sectional viewsshowing electrodes in contact with tissue for ablation.

FIG. 8 is a schematic representation of an alternative embodiment of ahemostasis device.

FIG. 9 is a schematic representation of another alternative embodimentof a hemostasis device.

FIG. 10 is a schematic representation of a cylindrically shapedembodiment of a hemostasis device.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

A method and system for achieving hemostasis (the stoppage of bleeding)is described. RF (radio frequency) energy is used to ablate the surfaceof tissue to stop bleeding. The depth of destruction of the tissue canbe controlled so as to desiccate and coagulate the superficial tissue,without causing additional or unnecessary injury. An electrode carrierincluding bipolar electrodes can be applied to the tissue, and RF energytransmitted through the bipolar electrodes to ablate the tissue. A layerof desiccated tissue, e.g., approximately 1 mm thick, can be created aswell as coagulation of the tissue to achieve hemostasis. The electrodecarrier can be removed without restarting the bleeding, nor doespressure need to be applied after desiccation is complete.

Referring to FIG. 1A, one embodiment of a hemostasis device 100 isshown. The base member of the hemostasis device 100 is configured as aglove and includes one or more electrode carriers. In the embodimentshown, a first electrode carrier 102 is included in the palm of theglove shaped hemostasis device 100, and five narrower electrode carriers104-112 are included on the fingers and thumb of the hemostasis device100. The glove-shaped hemostasis device 100 can fit over a user's hand,and is flexible so that the fingers can be extended or curled, etc., asdesired by the user. The electrode carriers can have differentconfigurations, e.g., the electrodes can extend along the proximaland/or distal ends of the palm and/or fingers.

Referring to FIG. 1B, in another embodiment of the hemostasis device101, the electrode carriers are on the exterior surface of the gloveshaped device, i.e., on the “top side” of the hand rather than on the“palm side”. In the embodiment shown, a first electrode carrier 103 isincluded on the top of the glove shaped hemostasis device 101, and fivenarrower electrode carriers 105-113 are including on the tops of thefingers and thumb. In one application, a user can position thehemostasis device 101 within a cavity, e.g., a uterus, and form a firstto achieve hemostasis of the tissue within the cavity. In yet anotherembodiment, electrode carriers can be included on both the palm side andtop side of the glove shaped device, or can be included on the fingersonly or the palm and top of the hand only. Other configurations arepossible.

Referring again to FIG. 1A and to FIG. 2, an enlarged view is shown of aportion of the first electrode carrier 102. The electrode carrier 102 isformed from a woven insulative base material 114, which in oneembodiment can be thin, plastic strips. Woven between the strips of basematerial 114 are electrodes 116. In this embodiment, the electrodes 116are gold plated copper wires and two electrodes 116 are woven betweeneach strip of base material 114. The electrodes 116 can be oppositelycharged between each strip of base material 114. That is, electrodes 116a can be positively charged, and electrodes 116 b can be negativelycharged, with the strip of base material 114 providing a non-conductiveregion between the bi-polar electrode regions 116 a, 116 b. In anotherembodiment, a single electrode 116 can be woven between each strip ofbase material 114, with each electrode 116 alternating conductivity. Inyet another embodiment, more than two electrodes 116 can be wovenbetween each strip of base material. A pair of oppositely chargedelectrodes (or a pair of sets of electrodes) is referred to herein as a“bipolar electrode”. Referring again to FIG. 1A, the electrodes 116 areelectrically coupled to a connector 118 that can be electrically coupledby a cable 120 to an RF generator.

Referring to FIG. 3, a cross-sectional view is shown of the portion ofthe first electrode carrier 102 shown in FIG. 2 taken along line 3-3.The body 122 of the glove shaped hemostasis device 100 can be formedfrom a relatively thin and flexible material, e.g., nylon. As part ofthe body 122, or as a separate layer, a thermally insulating layer isincluded to protect the user's hand from temperatures generated duringuse of the hemostasis device 100 (e.g., from steam created from tissuedesiccation). The electrode carrier 102 includes a porous layer 124between the body 122 of the glove and the strips of base material 114and electrodes 116. A vacuum line 126 is included within or under theporous layer 124 and is coupled to a vacuum port 128 that can beconnected by a fluid line 130 to a vacuum source (FIG. 1). The porouslayer 124 is configured such that when vacuum is applied through thevacuum line 126, tissue can be drawn into contact with the electrodecarrier 102; the porous layer 124 facilitates spreading the vacuum overthe surface of the electrode carrier 102. In one embodiment, the porouslayer 124 can be formed from nylon and/or spandex. An electrode 116 isshown woven between the strips of base material 114.

Referring to FIG. 4, a system is shown including the hemostasis device100, an RF generator 140 and a vacuum source 142. The RF generator 140is coupled to the hemostasis device 100 by the cable 120. The vacuumsource 142 is coupled to the hemostasis device 100 by the fluid line130. In one embodiment, as shown, the vacuum source 142 can be activatedby a foot pedal 144, to allow an operator of the hemostasis device 100to keep both hands free to work with the bleeding tissue. In anotherembodiment, the RF generator 140 and the vacuum source 142 are combinedinto a single RF controller unit, which includes the RF generator,vacuum source, a vacuum monitoring system as well as a foot pedal 144for activating both the RF energy and the vacuum. Additionally, a userinput device including a display (e.g., similar to user input device 146shown) can be included in the single RF controller unit.

In one embodiment, an operator can control which electrode carriers102-112 are activated when using the hemostasis device 100. That is, fora particular application, using the palm electrode carrier 102 alone maybe desirable. In an alternative application, for example, where a fingerelectrode carrier 106 can be placed over a cut in damaged tissue, it maybe desirable to only activate the finger electrode carrier 106, so asnot to unnecessarily ablate healthy (i.e., undamaged) tissue in contactwith other parts of the hemostasis device 100. The RF generator 140 canbe connected to a user input device 146 to receive instructions from auser as to which electrode carriers to activate.

In the embodiment shown, the user input device 146 includes a touchscreen display 148. A visual representation of the hemostasis device 100is shown on the touch screen display 148. Each electrode carrier on thehemostasis device 100 is represented by a corresponding graphicrepresentation on the touch screen display 148. Once touched, theelectrode carrier graphic becomes highlighted, indicating it has beenselected, and by touching the graphic a second time, the electrodecarrier is deselected. For example, by touching an area of the touchscreen display 148 representing the palm electrode carrier 102, the RFgenerator, when activated (e.g., by depressing a foot pedal 144), isinstructed to transmit RF energy to the palm electrode carrier 102.

In one implementation, routing the RF energy in this manner can beaccomplished by having separate electrical connections, or pins, fromthe RF generator to each electrode carrier. Selecting a certainelectrode carrier on the touch screen display 148 instructs the RFgenerator to close the switch to the pin of the corresponding electrodecarrier on the hemostasis device 100. In this manner, once RF energy isinitiated, the RF energy flows to only those electrode carriers thathave been selected on the touch screen display 148. The user can selectto activate some or all of the six electrode carriers 102-112. In oneembodiment, conventional touch screen technology can be used toimplement the touch screen display 148. Other types of user inputdevices 146 can be used, and the touch screen display 148 is just oneexample.

FIG. 5 shows a side view of the hemostasis device 100 in contact withdamaged tissue 150. Referring to FIG. 6, a process 200 for using thehemostasis device 100 to stop bleeding from the damaged tissue 150 shallbe described for illustrative purposes. The hemostasis device 100 isfirst positioned by the user in contact with the damaged tissue 150(step 202). The user can exercise his/her discretion as to how thehemostasis device 100 is positioned, depending on the configuration ofthe tissue 150 to be treated. For example, the electrode carriers to beactivated can be selected by the user or an assistant selectivelytouching the corresponding areas on the touch screen display 148 (step204). The vacuum source 142 is activated, e.g., by depressing foot pedal144 (step 206), causing the damaged tissue 150 to be drawn into closercontact with the hemostasis device 100, and simultaneous evacuation ofblood, vapors and/or other material. The RF generator 140 receives theinput from the user input device 146 and transmits RF energy to theselected electrode carrier 102 (step 206).

The damaged tissue 150 is ablated in the area in contact with theelectrode carrier 102 until a desired depth of destruction is reached(step 208). The region 152 depicted in FIG. 5 represents the desiccatedtissue. The RF energy and vacuum are ceased (step 210) and thehemostasis device 100 can be removed from the tissue 150 (step 212).Ablating the upper surface of the bleeding tissue, e.g., to a depth ofapproximately 1 to 7 mm, depending upon the type of tissue treated,desiccates and coagulates the tissue and achieves hemostasis. Becausethe bleeding has ceased due to desiccation of the tissue, rather thandue to the application of pressure, the hemostasis device can be removedwithout restarting the bleeding. Optionally, a non-stick coating can beapplied to the surface of the hemostasis device 100 to promoteseparation from the tissue after hemostasis is achieved and theprocedure is complete.

To achieve the desired depth of ablation, a controller included in theRF generator 140 can monitor the impedance of the tissue at theelectrodes 116 and include an automatic shut-off once a thresholdimpedance is detected. As the tissue 150 is desiccated by the RF energy,fluid is lost and withdrawn from the region by the vacuum 140 into theporous layer 124 and removed through the vacuum line 126. The vacuumdraws moisture released by the tissue undergoing ablation away from theelectrode carrier 102 and prevents formation of a low-impedance liquidlayer around the electrodes 116 during ablation. As more of the tissueis desiccated, the higher the impedance experienced at the electrodes116. By calibrating the RF generator 140, taking into account systemimpedance (e.g., inductance in cabling, etc.) and electrode carrierconfiguration (e.g., center-to-center distance between electrodes 116),a threshold impedance level can be set that corresponds to a desireddepth of ablation. Once the threshold impedance is detected, thecontroller shuts off the RF energy, controlling the depth of tissuedestruction. In an alternative embodiment, the RF generator 140 can bedesigned such that above the threshold impedance level the RFgenerator's ability to deliver RF energy is greatly reduced, which ineffect automatically terminates energy delivery.

The depth of destruction is a function of a number of factors, includingthe tissue impedance, center-to-center distance between the positive andnegative electrodes of a bipolar electrode and the surface density ofthe electrodes, as described further below. In one implementation, theuser input device 146 can be configured to permit a user to select thedepth of destruction, for example, by selecting the surface density ofelectrodes and/or center-to-center distance between the electrodes.

As described above in reference to FIG. 2, more or fewer electrodes 116can be woven between each strip of base material 114, thereby increasingthe surface density of the electrodes 116. If greater ablation depth isdesired, more electrodes 116, e.g., five, can be woven between eachstrip of base material 114. Additionally, increasing thecenter-to-center distance between the positive electrode and negativeelectrode of a bipolar electrode can increase the depth of destruction.In the present example, a first set of five electrodes 116 can bepositively energized and the adjacent set of five electrodes 116negatively energized, which pattern is repeated across the electrodecarrier 102. The entire grouping of 10 electrodes, i.e., the 5 positiveand 5 negative electrodes, together are one bipolar electrode. Thecenter-to-center distance between the set of positive electrodes and setof negative electrodes is thereby increased, which can increase thedepth of ablation.

Referring to FIG. 7A, preferably each electrode is energized at apolarity opposite from that of its neighboring electrodes. By doing so,energy field patterns, designated 222, 224 and 226 in FIG. 7A, aregenerated between the electrode sites and thus help to direct the flowof current through the tissue T to form a region of ablation A. As canbe seen in FIG. 7A, if electrode spacing is increased by energizing, forexample, every third or fifth electrode 220 rather than all electrodes,the energy patterns will extend more deeply into the tissue. See, forexample, pattern 224 which results from energization of electrodeshaving a non-energized electrode between them, or pattern 226 whichresults from energization of electrodes having two non-energizedelectrodes between them.

The depth of ablation is also effected by the electrode density (i.e.,the percentage of the target tissue area which is in contact with activeelectrode surfaces) and may be regulated by pre-selecting the amount ofthis active electrode coverage. For example, the depth of ablation ismuch greater when the active electrode surface covers more than 10% ofthe target tissue than it is when the active electrode surfaces coversonly 1% of the target tissue.

By way of illustration, by using 3-6 mm spacing and an electrode widthof approximately 0.5-2.5 mm, delivery of approximately 20-40 watts overa 9-16 cm² target tissue area will cause ablation to a depth ofapproximately 5-7 millimeters when the active electrode surface coversmore than 10% of the target tissue area. After reaching this ablationdepth, the impedance of the tissue will become so great that ablationwill self-terminate. By contrast, using the same power, spacing,electrode width, and RF frequency will produce an ablation depth of only2-3 mm when the active electrode surfaces covers less than 1% of thetarget tissue area. This can be better understood with reference to FIG.7B, in which high surface density electrodes are designated 220A and lowsurface density electrodes are designated 220B. For purposes of thiscomparison between low and high surface density electrodes, eachbracketed group of low density electrodes is considered to be a singleelectrode. Thus, the electrode widths W and spacings S extend as shownin FIG. 7B.

As is apparent from FIG. 7B, the electrodes 220A, which have more activearea in contact with the underlying tissue T, produce a region ofablation A1 that extends more deeply into the tissue T than the ablationregion A2 produced by the low density electrodes 220B, even though theelectrode spacings and widths are the same for the high and low densityelectrodes. Some examples of electrode widths, having spacings with morethan 10% active electrode surface coverage, and their resultant ablationdepth, based on an ablation area of 6 cm² and a power of 20-40 watts,are given on the following table:

ELECTRODE WIDTH SPACING APPROX. DEPTH     1 mm 1-2 mm 1-3 mm 1-2.5 mm3-6 mm 5-7 mm 1-4.5 mm 8-10 mm  8-10 mm 

Examples of electrode widths, having spacings with less than 1% activeelectrode surface coverage, and their resultant ablation depth, based onan ablation area of 6 cm² and a power of 20-40 watts, are given on thefollowing table:

ELECTRODE WIDTH SPACING APPROX. DEPTH     1 mm 1-2 mm 0.5-1 mm   1-2.5mm 3-6 mm 2-3 mm 1-4.5 mm 8-10 mm  2-3 mm

Thus it can be seen that the depth of ablation is significantly lesswhen the active electrode surface coverage is decreased.

Referring to FIG. 7C, if multiple, closely spaced, electrodes 220 areprovided on the electrode carrying member, a user may set the REgenerator 140 to energize electrodes which will produce a desiredelectrode spacing and active electrode area. For example, alternateelectrodes may be energized as shown in FIG. 7C, with the first threeenergized electrodes having positive polarity, the second three havingnegative polarity, etc. All six electrodes together can be referred toas one bipolar electrode. As another example, shown in FIG. 7D, ifgreater ablation depth is desired the first five electrodes may bepositively energized, and the seventh through eleventh electrodesnegatively energized, with the sixth electrode remaining inactivated toprovide adequate electrode spacing. A user can therefore not onlycontrol which electrode carriers are activated, but in oneimplementation can also control which electrodes are energized within anelectrode carrier to produce a desired depth of destruction.

Other embodiments of the one or more electrode carriers are possible.For example, referring to FIG. 8, in one embodiment, an electrodecarrier, e.g., the palm electrode carrier 302, can be formed of a fabricthat is metallized in regions to form the electrodes 316. The electrodes316 are conductive and alternate between positive and negative polarity.Non-conductive insulator regions 318 separate the electrodes 316. Forexample, the fabric can be a composite yarn with a thermoplasticelastomer (TPE) core and multiple polyfilament nylon bundles woundaround the TPE as a cover. The nylon bundles are plated with thin,conductive metal layers. This construction is flexible, and canfacilitate achieving close contact between the electrode carrier 302 andan irregularly shaped area of tissue. Other configurations for theelectrode carriers 102-112 are possible, and the above describedembodiments are merely exemplary electrode carriers.

The hemostasis device has been described with reference to an embodimentwhere the electrode carrier or carriers are on the surface of a glovethat can be worn by a user. Other embodiments of the base member of thehemostasis device are possible. For example, referring to FIG. 9, in oneembodiment the base member 400 can be a paddle with a handle. One ormore electrode carriers 402 can be affixed to the surface of the paddle400, which can be manipulated by a user into a position in contact withdamaged tissue. A porous layer is included beneath the electrode carrier402 and a vacuum source can be connected to a vacuum line within orunder the porous layer to provide vacuum at the electrode carriersurface, as described above in reference to the glove-shaped embodiment.

In one embodiment, the paddle 400 can be formed smaller than a humanhand, such that the paddle 400 can reach into areas that might otherwisebe inaccessible by a human hand if using the glove-configured hemostasisdevice 100. In another embodiment, the paddle 400 and electrode carrier402 can be formed larger than the palm of a human hand, such that theelectrode carrier 402 can be used to cover relatively large areas ofdamaged tissue, i.e., larger than can be covered by the palm electrodecarrier 102 of the glove-configured hemostasis device 100. Otherconfigurations of the hemostasis device are possible, includingdifferent shapes and sizes. The paddle 400, or otherwise configured basemember, can be flexible so as to conform to the surface of damagedtissue, or can be substantially rigid, which may be desirable in certainapplications.

The hemostasis device can be used to achieve hemostasis under urgent,life-threatening conditions, e.g., on a battlefield or at the scene ofan accident, or under controlled conditions, e.g., during surgery. Forexample, a soldier suffering an injury to the liver on the battlefieldis often at risk of bleeding to death within a considerably short periodof time. The liver is an organ that once damaged can bleed profusely,and the surface is such that the liver cannot simply be sutured to stopbleeding. The hemostasis device, for example the glove-shaped hemostasisdevice 100, can be ideal in such situations. A user, even underbattlefield conditions, can put on the glove-shaped hemostasis device100, reach into the soldier's body, find the damaged liver, activate thedesired one or more electrode carriers, and achieve hemostasis in a veryshort period of time. A soldier who may have otherwise bled to deathcould be saved using the hemostasis device 100.

The hemostasis device can also be useful in surgical procedures. By wayof illustrative example, consider a liver that has been diagnosed asincluding a tumor that must be removed to save a patient's life. Usingconventional techniques, to remove the tumor one or more incisions intothe liver would be necessary. Cutting into the liver tissue typicallytriggers profuse bleeding that can be difficult to control, even underoperating room conditions. The hemostasis device can instead be used toachieve almost immediate hemostasis, avoiding unnecessary blood lossfrom the patient. For example, after making an incision into the liver,a user wearing the glove-shaped hemostasis device 100 can lay a fingerover the incision and activate the electrode carrier corresponding tothe finger. RF energy transmitted to the activated electrode carrier canquickly achieve hemostasis.

In an alternative implementation, the base member of the hemostasisdevice 500 can be cylindrically shaped as shown in FIG. 10. One or morebipolar electrodes 504 can be positioned on the exterior surface of thehemostasis device 500. A cable 508 can connect the one or more bipolarelectrodes 504 to an RF energy source, and a fluid line 506 can connecta porous layer beneath the bipolar electrodes to a vacuum source.Optionally, a distal end 502 of the hemostasis device 500 can besharpened so the hemostasis device 500 can cut into the tissue whilebeing inserted into position. The hemostasis device 500 can be insertedinto tissue, for example, a liver including a tumor, so that the tumoris within the interior of the hemostasis device 500 when it ispositioned in the liver. The one or more bipolar electrodes 504 on theexterior of the hemostasis device 500 can be activated, and thesurrounding tissue ablated. The hemostasis device 500 and the tissuewithin the interior core can be removed from the liver. The tumor isthereby extracted from the liver, and hemostasis in achieved in thesurrounding tissue. In another embodiment, one or more bipolarelectrodes can be included on the interior of the hemostasis device 500.Other configurations are possible.

Other embodiments of the base member and hemostasis device are possible,and the ones described above are merely exemplary. Additionally, otherprocedures for using the hemostasis device are possible, and thebattlefield and surgical procedures described above were examples forillustrative purposes.

A number of embodiments of the invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the spirit and scope of the invention.Accordingly, other embodiments are within the scope of the followingclaims.

1. An apparatus for substantially achieving tissue ablation, comprising:a base member comprised of a porous layer; an electrode carrier attachedto a surface of the base member, the electrode carrier including abipolar electrode that is configured to connect to a source of radiofrequency energy; a vacuum line included within the porous layer of thebase member, the vacuum line being configured to connect to a vacuumsource and to draw moisture away from the bipolar electrode; and acontroller electrically coupled to the bipolar electrode and configuredto control the delivery of radio frequency energy to the bipolarelectrode such that tissue in contact with the bipolar electrode can beablated.
 2. The apparatus of claim 1, wherein the controller isconfigured to control the delivery of radio frequency energy based on animpedance of the tissue near the electrode carrier.
 3. The apparatus ofclaim 1 further comprising a second bipolar electrode included on theelectrode carrier that can be selectively activated by a user.
 4. Theapparatus of claim 1, wherein the base member is configured to bepositioned within a body cavity.
 5. The apparatus of claim 1, whereinthe controller is configured to alter the delivery of radio frequencyenergy after a threshold impedance is detected.
 6. The apparatus ofclaim 5, wherein the controller is configured to take into accountsystem impedance.
 7. The apparatus of claim 5, wherein the thresholdimpedance corresponds to a desired depth of ablation.